↑Hammarström, Harald; Forkel, Robert; Haspelmath, Martin; Bank, Sebastian, 편집. (2023). 〈Amkoe〉. 《Glottolog 4.8》. Jena, Germany: Max Planck Institute for the Science of Human History.
↑Güldemann, Tom; Fehn, Anne-Maria (2016). 《Beyond 'Khoisan': Historical Relations in the Kalahari Basin》. John Benjamins Publishing Company. 1-41쪽. ISBN9789027248497.|확인날짜=는 |url=을 필요로 함 (도움말)